It has long been known that lead shot expended, generally in hunting, that remains in the environment poses a significant toxic problem. The most severe problem presented by the spent lead shot is the ingestion by game fowl, particularly water fowl, of the spent shot for grit. Conventional shot, consisting or consisting essentially of lead, can lead to lead poisoning of the bird ingesting the shot. Estimates of water fowl mortality due to this type of lead poisoning ranges as high as 2-3% of all deaths per year.
These findings have generated a continual search for alternatives to conventional lead shot. Ultimately, steel (soft ron) shot was proposed as a substitute, as it is less expensive than more inert and softer metals (such as gold), resists erosion and produces no toxic effects when exposed to the acid environment of water fowl stomachs. Unfortunately, the cost of steel shot is higher than the cost of lead shot, and the steel is significantly harder than lead shot. As a result, steel shot can damage the barrels of most commercially available shotguns not designed specifically for shooting steel shot. Moreover, being substantially less dense than lead, steel shot is significantly inferior to lead, ballistically. This results in a high increase in the unnecessary loss of wild fowl due to crippling rather than kill shots. This increase has been estimated to be a higher increase in mortality than that due to lead poisoning.
Additionally, lead shot remaining in the environment is a source of lead introduced to the environment, that can be inadvertently included in a variety of food chains, not only water fowl. The natural acidity of rain fall, coupled with many acid environments, leads to leaching of the lead, and potential poisoning of important habitats and environments.
One alternative to conventional lead shot is discussed in U.S. Pat. No. 3,363,561, Irons. As described therein, TEFLON is coated over lead shot, for the purposes of preventing lead poisoning. The process as described for coating the lead shot at column 3, lines 19-45 of the Irons patent, uniformly call for the application of TEFLON at temperatures only up to 400.degree. F. so as to avoid deformation of the shot which starts to lose its shape around 425.degree. F. Polymers exhibiting the levels of corrosion resistance and abrasion resistance necessary to be effective in significantly reducing or eliminating lead leaching require temperatures in excess of 400.degree. F. to cure and bond satisfactorily. Most of the processes call for temperatures about 400.degree. F. This results in a thin coating of polymer about an internal lead shot, but no significant bonding between the polymer and the shot. As a result, the polymer is easily peeled from the shot, and in fact, significant erosion or destruction of the polymer coating can occur in the mechanical environment of the shotgun barrel. Accordingly, this alternative has not received success in the industry.
It therefore remains a goal of those of skill in the art to provide ballistically acceptable, environmentally safe and lead erosion-free shot.